A standard tennis court is constructed on a platform that allows movement in all three dimensions. The court is calibrated to center position, and a large ball, almost a foot in diameter, is lowered from the ceiling by slender metal pipe, stabilizing it. The metal pipe contains electrical wires
inside, and it extends into the middle of the ball.

The outside of the ball is covered in sensors that record the impulse from the racquets. When Bill strikes the ball, instead of the ball moving forwards, the court moves backwards. Gravity, too, is calculated by the computer, so if Bill lobs the ball, the court will move down and up in perfect parabolic fashion.

The sphere at the center of the court has a theoretical mass of 1kg, and all calculations use this amount of mass. This means that if you transfer 5kg-m/s north of momentum into the sphere, the court will move south at a velocity of 5m/s. In actuality, the sphere may be many kilograms.

NB. The theoretical mass of the sphere is not set in stone; it can be altered if the court is moving too quickly. Acceleration due to gravity (g) can also be changed to give the effect of playing on the moon.

Serving Suggestionhttp://hypertextboo...01/TinaCheung.shtmlYou might have problems with deccelerating an entire tennis court from 263 km/h (164 mi/h). And then there's the bouncing before the serve. [Detly, Dec 11 2004]

I love this idea. It's the hope of stumbling upon stuff like this that keeps me coming back to the HB.

I'd like to watch it on TV, with all the cameras embedded in the walls of the court. The court would always appear stable, but suddenly, for no apparent reason, a successful overhand smash would result in both players dropping to the ground and holding on for dear life.

Good tennis players put serious spin on the ball occasionally. Are you telling me the court is going to spin around the ball? Cause I'm OK with that, as long as I wait an hour after eating before I play.